Diagram from the B&M website should clear this up. The answer to whether it can hurt your transmission or not? Yes and no. You can hurt your transmission with a normal shifter by using too much force, trying to shift to fast (sychros can't engage quickly enough, bear in mind that we have constant-mesh transmissions, you are not moving gears around, just which one is connected to the drive shaft), or not using the clutch correctly. A shorter level and ratio means if you are not precise, you have a higher chance of the above problems. Think of it this way, if you grab your shift level 35 mm below the top of the knob , and shift holding it there, are you gonna hurt anything. no.

Good diagram. But this looks like the "modified" shifter is changed at both ends. Both links changed. The original post, I thought, just talked about changing the Knob end shorter by 35mm. Or said another way if you modify a standard shifter by shortening the top link nothing else changes. Seems like this should work also. With slightly different results?? This diagram also indicates that both ends change when going from stock to STS.